Installing RHEL4 on Systems with Legacy Megaraid Drivers

This page has been far more popular than I ever imagined.  It get's several hundred hits a month and I get quite a few emails from people having various problems.  I try to make changes when they are appropriate, but this was mainly written as a quick summary of what I did, it's not exactly a perfect, step-by-step instruction.  There have been quite a large number of success reports, but many people also really struggle.  I try to answer people that email me, but some have complained that I don't respond fast enough.  I'm sorry, I really do try, but based on work and personal responsibilties I don't always have time to answer right away.  Various mailing lists may be more appropriate if you're looking for more immediate help.

Purpose

Procedure to install RHEL4 on systems with unsupported Megaraid controllers such as the Dell PERC2/DC controllers.  Actually, this is a pretty generic process that, with minor modifications, should work with any driver which you have source, and a machine on which to compile it.

Requirements

A system with and old style megaraid adapter -- otherwise, what's the point?

An already installed RHEL4 system (or possibly FC3 system or other system with GCC 3.4) with the kernel-devel rpms that match your install media (for example 2.6.9-11 for RHEL4 U1)

Getting Ready

On your working RHEL4 system make sure you have the kernel-devel packages installed that match the kernel on your install media (2.6.9-5.EL for RTM, 2.6.9-11.EL for U1).  Create a directory to hold the megaraid source code from the 2.6 kernel.  Click here to download the required driver source code included in the Redhat 2.6.9-11.EL kernel source package, which I would think it would be fine for most any kernel.

# mkdir /usr/src/megaraid
# cd /usr/src/megaraid
# tar jxvfp /usr/src/sofware/megaraid2.tar.bz2

Compile the Driver

Now comes time to compile the driver.  This is a pretty simple process that should be similar to the following:

# make -C /lib/modules/2.6.9-11.EL/build SUBDIRS=/usr/src/megaraid modules

This should compile the required module.  Obviously if you used different directories or are compiling for a different kernel then you will need to modify the above line for this adjustments.  The compile will also produce a few warning but it seems safe to ignore these.  Once this is complete you should have a megaraid.ko file in the directory.  Simply copy the file to a floppy and your ready to start your install.

Install RHEL4

Start the install by booting from the CD and typing "linux noprobe" from the boot prompt.  This will keep the installer from probing and attempting to detect your hardware.  While still in the text portion of the install you will be prompted to pick your hard drive controller, since the driver is not going to be in the list now it's the time to manually install your driver using the following steps:

1.  Press Ctrl-Alt-F2 to switch to a bash prompt

2.  Insert the floppy that contains your megaraid.ko file

3.  Create directory, mount floppy, install the module:

     # mkdir /mount/floppy
     # mount /dev/fd0 /mnt/floppy
     # insmod /mnt/floppy/megaraid.ko

4.  Verify that the module loaded by typing "lsmod" and seeing if megaraid is listed

5.  Verify that your RAID array was found by pressing Alt-F4 and seeing the output from the module load

Hopefully at this point everything looks good.  At this point complete switch back to the normal install screen by pressing Alt-F7.  Since you've manually loaded the driver from the command prompt you can ignore this screen's instructions to pick a driver, simply pick the option to continue the install.  Anaconda should load and the GUI portion of the install should begin.  Complete the install as normal, with one exception, after all packages are installed and the system prompts you to press finish to reboot Don't do it, proceed to the next section!  (If you make a mistake here it is recoverable by booting in rescue mode, but it's more steps).

Complete the Install

Because the megaraid driver was installed manually the installer will likely not build a proper initrd.  We can fix this before the reboot right now with the following steps:

1.  Press Ctrl-Alt-F2 to switch from the GUI to a bash prompt

2.  Copy the megaraid.ko module with the command 'cp /mnt/floppy/megaraid.ko /mnt/sysimage/lib/modules/2.6.9-11.EL/kernel/drivers/scsi'

3.  Type 'chroot /mnt/sysimage' to set your root to your newly installed system image

4.  Type 'vi /etc/modprobe.conf' and make sure that the line with 'alias scsi_hostadapter' says 'alias scsi_hostadapter megaraid'.  Save the file.

5.  Switch to the /boot directory 'cd /boot'

6.  Create new initrd file 'mkinitrd initrd-2.6.9-11.EL.img.megaraid 2.6.9-11.EL'

7.  Copy the new initrd over old initrd 'cp initrd-2.6.9-11.EL.img.megaraid initrd-2.6.9-EL.img'

8.  Exit chroot environment by typing exit

9.  Switch back to the GUI installer with Alt-F7 and press Finish

After these steps your system should be able to boot up a UP kernel.  If your installing on an SMP section you'll need to boot up the UP system, compile the source driver again for the SMP kernel, install the module, recreate the initrd for the SMP kernel, and reboot again.

Why?

Why in the world would you go through this effort?  The reality is, I have no idea.  Fedora Core 4 installs fine on systems with these controllers, and for a 2.6 enterprise distribution, SLES9 works fine.  If your totally stuck on Redhat then I'd suggest that you learn to be happy with RHEL3.

That being said, some of us are gluttons for punishment.  We have several totally usuable servers that run RHEL4 great except for the lack of support for the Dell PERC2/DC's.  After doing this once or twice I can now install RHEL4 on systems with these controllers in only a few minutes, and upgrading a kernel takes only a few minutes extra for each machine, so, once you've practiced a few times it's not that bad.

Besides, it was a personal challenge.